14. Exercises

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</div>{{#NAVCONTENT:Answer|Answer 14.1|Solution a|Solution 14.1a|Solution b|Solution 14.1b}}
</div>{{#NAVCONTENT:Answer|Answer 14.1|Solution a|Solution 14.1a|Solution b|Solution 14.1b}}
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===Exercise 14.2===
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A plank has length 6 m. The plank is placed on a quayside with its mid-point at the edge of the quay, so that half of the plank sticks out over the water. A rock of mass m kg, which should be modeled as a particle is placed at the end of the plank which is on the ground. A person of mass 60 kg walks on the part of plank that is over the water. When the person is 1 m from the end the plank is on the point of tipping. Find m.
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[[Image:E14.2.GIF]]
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</div>{{#NAVCONTENT:Answer|Answer 14.2|Solution|Solution 14.2}}

Revision as of 19:32, 9 November 2009

       Theory          Exercises      


Exercise14.1

A uniform beam of mass 20 kg and length 3m rests on two supports as shown below.

Image:E14.1.GIF

(a) Find the reaction force exerted by each support.

(b) Find the greatest mass that can be placed at the left hand end of the beam.



Exercise 14.2

A plank has length 6 m. The plank is placed on a quayside with its mid-point at the edge of the quay, so that half of the plank sticks out over the water. A rock of mass m kg, which should be modeled as a particle is placed at the end of the plank which is on the ground. A person of mass 60 kg walks on the part of plank that is over the water. When the person is 1 m from the end the plank is on the point of tipping. Find m.

Image:E14.2.GIF